There are millions of business-critical .NET Framework assemblies with no source code. ProvenPort modernizes them to modern .NET — and is the only approach that proves the result behaves identically to the original.
Problem
.NET Framework powered enterprise software for two decades. Today it is legacy — no new features, mounting security and compliance pressure — yet enormous amounts of it survive only as compiled binaries: source lost, vendors vanished, authors moved on.
Reverse-engineering yields code that frequently won't rebuild — and even when it does, no one can vouch for it.
The modern runtime silently changed subtle behaviors. A "successful" port can be quietly, dangerously wrong.
These are payroll engines, trading libraries, medical and industrial components. "Probably fine" is not an acceptable migration standard.
So the binary stays frozen — accumulating risk — because the safe path doesn't exist. Until now.
Solution
We don't ask you to trust modernized code. We measure it: establish the original binary's exact behavior, reproduce the same conditions on modern .NET, and compare. Differences are reconciled with verified, behavior-preserving changes until the old and new builds agree.
The output isn't just a modern build.
It's a modern build with a proof.
Why now
.NET Framework is end-of-the-road; security, compliance, and talent scarcity are forcing migration decisions now.
AI collapses the cost of the long tail of edge cases — but only when wrapped in a system that can measure binaries and verify every change.
The hard part lives deep in .NET internals — exactly where general-purpose AI fails and few engineers can operate.
Defensibility
Conversion is a commodity. The defensible asset is the verified know-how that makes a port faithful — and the ability to prove it. Both grow with use.
A growing library of verified, behavior-preserving techniques, accumulated from real binaries — expensive to rebuild and widening with every engagement.
Every binary we process expands what the system can handle. The product gets more capable — and harder to copy — the more it runs.
Equivalence is established by measurement, turning "trust me" into an auditable result — the thing enterprises need to sign off a migration.
Two decades inside .NET binaries. This is not an advantage you assemble from a weekend prototype.
Traction
For each library we modernize the legacy binary, then run the library's own test suite against the modernized assembly. Third-party validation, not self-reported demos.
| Library | Domain | Tests passing | Status |
|---|---|---|---|
| MathNet.Numerics | Numerical computing | 20,908 / 20,958 | validated |
| Humanizer | Text & localization | 15,023 / 15,023 | validated |
| Markdig | Markdown parser | 3,795 / 3,796 | validated |
| CsvHelper | CSV parsing | 1,058 / 1,058 | validated |
| YamlDotNet | YAML serializer | 885 / 890 | validated |
| Fastenshtein | String distance | 28 / 28 | validated |
In one library, the modernized build initially diverged on a specific input — a genuine behavioral change introduced by the modern runtime, invisible at build time. ProvenPort detected it, pinpointed the cause, and restored the original behavior. That's the entire value proposition in a single case: a migration that doesn't just convert — it knows the behavior is identical.
Market
Financial, healthcare, industrial, and government systems carrying source-less .NET Framework components into a modern stack — under audit and compliance scrutiny.
System integrators and acquirers who inherit undocumented binaries and need a defensible, evidence-backed path forward.
Migration is a board-level mandate with a hard deadline and no good options. ProvenPort is the option that comes with a receipt.
Author
Principal Engineer on Microsoft's Visual Studio Tools for Unity. Creator of Reflexil, the widely-used .NET IL assembly editor. Co-founder of DataGalaxy. Two decades operating in exactly the domain ProvenPort requires — IL, decompilation, debuggers, and .NET runtime internals.
ProvenPort's advantage is not a clever prompt; it is accumulated, verifiable engineering in a domain most teams cannot enter.
The ask
We're partnering with a small number of organizations that have source-less .NET Framework binaries on the critical path to modernization. You bring a real binary and its acceptance criteria; we deliver a modern build with a proof — and shape the product around your evidence requirements.
Become a design partner →hello@provenport.ai